1. Field of the Invention
The present invention relates to a semiconductor device that includes a bonding pad, to which an external connection wire is bonded.
2. Description of Related Art
A technique for bonding an external connection wire to a bonding pad of a semiconductor device is disclosed in, for example, Japanese Unexamined Patent Publication No. 11-233553. In this technique, a gold conductive line is used as an external connection wire, and an opening, which corresponds to a gold bulb formed on a bonding pad, is formed through a passivation film provided on the bonding pad. With this arrangement, the opening of the passivation film is closed and is sealed by the gold bulb, and exposure of the bonding pad connected to the gold bulb is prevented. In this way, corrosion of the bonding pad by, for example, water is restrained.
However, in the above prior art technique, the formation of the gold bulb, which seals the opening of the passivation film provided on the bonding pad, requires precise control of a size of the gold bulb and positioning of the gold bulb. This normally results in a time consuming manufacturing process.
Furthermore, Japanese Patent Number 2536419 discloses a semiconductor device that includes bonding pads and probe pads, which are alternately arranged on a common surface. Each bonding pad and the corresponding probe pad extend downwardly through corresponding through holes provided in a dielectric film and are then connected to a common lower wiring layer. In such a case, even when the exposed bonding pad is corroded, the bonding pad is electrically connected to an internal electronic circuit of the semiconductor device through the corresponding through hole and the lower wiring layer. However, formation of the through holes in the dielectric film and filling of conductive material in the through holes require more complicated manufacturing process and more complicated semiconductor device.
Thus, it is desired to develop a technique for bonding an external connection wire only to a portion of a predetermined exposed region of a bonding pad exposed through an opening of a passivation film provided on the bonding pad while restraining corrosion of the bonding pad in a relatively simple manner. It is an objective of the present invention to address the above disadvantages and thus provides the above desired technique.
To achieve the objective of the present invention, there is provided a semiconductor device that includes a substrate, a bonding pad, a passivation film and an external connection wire. The bonding pad is located on one side of the substrate. The passivation film is provided on the bonding pad and has a bonding pad opening, through which a predetermined exposed region of the bonding pad is exposed. The external connection wire is externally connected and is bonded to a portion of the predetermined exposed region of the bonding pad, which is exposed through the bonding pad opening of the passivation film. The bonding pad opening of the passivation film has one of a polygonal shape, a generally circular shape and a generally ellipsoidal shape. The polygonal shape has a plurality of corners, and each of the plurality of corners has an obtuse angle or is chamfered.
To achieve the objective of the present invention, there is also provided a method for testing a semiconductor device. According to this method, a distal end of an inspection probe is engaged with a probe engaging point of a predetermined exposed region of a probe pad, which is exposed through a polygonal probe pad opening of a passivation film. Then, electrical voltage is applied from the inspection probe to the probe pad to test electrical characteristics of the semiconductor device. Here, the probe pad is electrically connected to a bonding pad through a conductive line covered with the passivation film. The bonding pad is externally connected through an external connection wire, which is bonded to a portion of a predetermined exposed region of the bonding pad that is exposed through a bonding pad opening of the passivation film. The polygonal probe pad opening of the passivation film has a plurality of corners, and each of the plurality of corners has an obtuse angle or is chamfered. The conductive line extends along an imaginary center line, which connects between a center of the bonding pad and a center of the probe pad. A distance in a direction perpendicular to the imaginary center line between the imaginary center line and a closest one of the corners of the probe pad opening, which is closest to the imaginary center line, is equal to or less than a distance along the imaginary center line between a probe engaging point of the probe pad, which is engaged with the inspection probe at time of testing the semiconductor device, and a bonding pad side edge of the probe pad opening.